compositions



-. COMPOSITIONS,

COATING R PLASTIC.

b\l% l 'atented Sept. 2, 1924. 0

UNITED STATES WILLIAM HOSKINS, OF CHICAGO, ILLINOIS, ASSIGNOR T0 ECONOMYFUSE 6'0 MANU- FACTU ANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEWYORK.

PLASTIC.

No Drawing.

T 0 all it may concern Be it known that 1, WILLIAM HOSKINS, a

. citizen of the United States, residing at 111 West Monroe Street,Chicago, in the county of Cook and State of Illinois, have invented newand useful Improvements in Plastics, of which the following is aspecification.

In accordance with the present invention a cement is prepared byadmixing with an inert material a primary binding constituent which willcause the cement to set when treated with a solution of phosphoric acid,this binding material being an aluminate of a metal of the alkali oralkaline earth groups. The primary bindin constituent of the oement mayb prepaggiby mtimatelv admixing alumina or alumi 1 d d m eor car )01'18o 0 pren in equimolecular proportions or in excess, the excess of thecalcined alumina being, in the latter case, incorporated in the cementas a part of the inert material or filler. The temperature of calciningshould be sufliciently high to cause reaction, but may in general be nothigher than intering tem erature. With higher temperatures care must betaken to avoid decomposition of the aluminate. A temperature ofapproximately 1000 C. (and below 1300 C.) is satisfactory for theproduction of the aluminate in substantially all cases. Thus 100 partsof calcium carbonate and 140 parts of aluminum hydroxide (equimolecularproportions) may be calcined at 10001100 C. until no more CO is evolved,the resulting al minate materialbeing a bindin mater'lal suitable m e inApplication filed March 17, 1921. Serial No. 452,953.

for example, of sufficient fineness to pass inert or non-Bonding Ellalumina and the like, the propo 1OI1 0 Binding material being not lessthan 2% of the whole.

The ro ortio f binder resent influences therata thegreaterje pro,- por-1OI1 o f bind.er the.mone rapid the set. In

gem-175171501 technical purposes, 1t"'i"' preferred that the ro ortio'nof binder; do not exceed 10%, as W1 more an of the alumina 'e in er therate of setting is too rapid for general technical use. With 2% of thealuminate binder in the mixture a temperature above ordinary atmospherictemperature is necessary to produce a set in a reasonable time, atemperature of 100150 C. being preferred. With 34% of aluminate binder,say, calcium aluminate, a period of above 30 days is required forsetting at ordinary temperatures, the final set not be reached for 2 to3 months; at 110115 from 12-24 hours is required, and at 140- 150 C. 2to 3 hours is sufiicient for the set although a longer period, say, 10to 12 hours or more is preferred. In very rapidly setting cements, suchas dental s, theproportion of binder emp oye exceeds 10%, and may be ashigh as 65-75%.

A ma 'al may be employed as a fillerand any suitable inert pigmentmaterials may be used for coloring the cement. The tensile strength ofthe material is affected by the character of the filler, a highertensile strength being secured with materials and 7 parts of calcium carna e. ca cinmg of sharply angular character, particularly e excess ofalumina in the ca cine mixture is incorporated in the cement as a partof the filler.

Anip xide, hydrate or carbonate of any metal of the alkali an a a meearth groups for thewamfiifitrgzbonate tensile strength.

in the above example in w o e or 1n par d1 m carbonate. t.

'e 0., may uemp oye t is preferred that the constituents of the mixtureto be calcined be very finely gound er, such as silica the desired proertie final molded article, such as arium sulfate asbestos fiber owder ca a umina.

o irne sum an ma neslte etc. 1 ers 5 such as calcmed'alumma andhydraulic gypsum inffiience the rate of set oy reason of eir facility ofcombination with water, thereby increasing the concentration of thesetting liquid. They are, however, inert in that they do not otherwiseappear to partake in the setting reaction. The greater the proportion ofsuch fillers, other factors being the same, the slower the set, in themeasure that the concentration of the setting liquid 16 is increased bythe dehydrating action of the filler constituent. With increase inconcentration an increase in the tensile strength of the molded articleis found.

, The setting liquid to be admixed with the 0 cement to produce theplastic material is a solmjoF of phosphoric acid. which may, if es1recon aln 10s 1a es. A liquid suitable for use in commerclal practice maybe prepared by mixing 308 parts by weight of 2 85% hos )horic acid. 60parts by weight of zinc oxide and parts by weight of water. lheproportions of the constituents may be varied and the zinc oxide may beomitted entirely or may be partially or completely 30 replaced by otheroxides or phosphates, for

example, aluminum oxide, sodium hydroxide. sodium ahos hate. etc. lime,in the manufacture of synthetic porcelains or dental cements, the zincoxide or any substitute 36 therefor, may be omitted. the liquid thencontaining phos horic acid and water. The concentration omthe liquidinfluences the rate of setting and the tensile strength of the moldedarticle, as with concentrations of phosphoric acid above that set forthsupra, the filler remaining un changed. the rate of setting is decreasedand the tensile strength increased. The concentration of phosphoric acidmay be varied by varying the relative proportions of phos phoric acidand water in the mixture. or. as hereinbefore set forth, it may also bevaried by the use of dehydrating fillers. that is. fillers capable ofchemically combining with water and thereby increasing the concentra--tion of the phosphoric acid. The proportion of liquid to cement shouldbe suflicient to cause at least a wetting of the particles of the cementby the liquid. In the case of com 1 dits. intended tomenfild'eflffdnexam e. 1111 .er pressure in ms, the ro or, tifiiigui hogld not be sogrea% ma e tie mass stickly or tacky when compressed. Thus, with acement containing about 3% of binder, that is, calcium aluminate, andwith quartz and alumina as fillers the proportion of liquid of thespecific composition above set forth may suitably be about parts to 100parts of cement (by 65 weight).

which are employed in a highly fplastic state and contain largeproportions o the binder, much larger proportions of the setting liquidmay be used; for example, the setting liquid and cement may be in equalproportions by weight.

It is readily apparent that cements prepared in accordance with thepresent invention may be controlled within wide limits as to theirbehavior, particularly in setting. and that their physical character maybe greatly varied. As an example of a cement which can be used for coldmolding, I may prepare a mixture of one part ignited alumina and twoparts of silica, preferably in the form of crushed quartz, and add tothe mixture 3% of calcium aluminate binder, prepared as above set forth.The mixture, preferably finely ground to about 200 mesh or less andthoroughly mixed, is admixed with setting liquid, for example, of theproportions described above for use in commercial practice, the liquidand the cement being in the proportion of about 1 to 8 by weight. Themixture is plastic under pressure and 11121V b 6 molded into the desiredfor in a cold press under a suitable pressure, say 2 25 tons or hi her.When the mixture is fFesh itmency to stick to the dies. This tendencyappears to disappear after the mixture has aged somewhat, say 12 hoursor longer. The pressed article has sufiicient coherence to permithandling. At ordinary temperatures upwards of a month is required tocause it to set. By heating to 110 to 115 C. it may be caused to set inabout 12 hours or more, a longer time being preferred. At a temperatureof 140 to 150 an initial setting may be effected in one-half to onehour; a longer setting period, say 12-18 hours is preferred. The plasticmixture of cement and liquid may be molded for a considerable periodafter it has been admixed. provided it is kept at ordinary temperatureor cooler. It molds well even after ten days to two weeks standing.

As has been set forth earlier in this specification, the fillerconstituents of the cement may be greatly varied. Thus, in the precedingexample, the proportions of alumina to .silica may be one to four, theresulting molded article, after setting, having very nearly the sametensile strength and hardness as one prepared from a mixture of one partalumina and two parts silic In either case the final material has atensile strength equal to or ment. u I: 0| 0 which the final articleappears to be less hard than when silica is used in the filler.

S1l1' 'ca alone may likewise be employed. Either t e a umina or thesilica, or both. may be replaoedi whole or in other exceeding that offillers, such as crushed glass, asbestos fiber. With cements for dentaluse dead burnt or hy raulic gypsum, dead burnt u. UUMIUSIIIUNS,

COATING R PLASTIC.

magliesite, etc., the characteristics of these fillers having alreadybeen set forth. Organic fillers of an inert character, such as 's nd thelike may e emp oye. 1th such fillers there is, however, a tendency todiscoloration by carbonization when the final article is set withthe aidof heat. Pigment fillers may, of course, be employed as desired. If morerapid setting is desired, higher proportions of the binder may be used.Although in the exam le calcium aluminate is stated to be the indemnyaluminate of an alkali or an alkali earth metal ma Y be employed, ormlxtures thereof may e used, as fully set forth earlier 1n thespecification.

Where alumina is used in the filler, as in the previous instance, anexcess of alumlna may be calcin sintemi me a or alkali n, me a co ounemp over to form the bin a 0 re Oma er thus formed admix with theremaining constituents of the cement, proper allowance being made forthe excess of alumina present in the binder.

In the setting of the cement there is substan la y no con raction andconsequently hard molded articles may be made therefrom dition withoutpressure, and is to set rapidly, higher proportions of binder and ofsetting liquid should be employed than in the case of commercial cementintended for molding. Thus, by using a cement contain- 70 in to ofaluminatwinder and mixifigtmmliaiijqual proportion of setting liquid, ahighly plastic material is obtained which, at ordinary temperatures,will set in five minutes or less. In the mixing of such a material it isadvisable that artificial cooling be employed to retard setting. Theplastic material may be readily molded into shape and set.

In such a cement translucency can be secured by use of crushed quartz orcrushed lass as a filler. l lillfilliw gd t at the setting liquidcontain no zinc 0Xl( eT'" zinc phosphate or other phosphates, but consgtsolely of phosphoric acid and Water.

For the formation of electric heatlng bodies, a suitableheatangelemantmybe mbedde i i n-.thewcement, and secured toti ininals which may, ifdesired, likewise be embedded in the cement. The hgating el ment maysuitably be of nickel chromium alloy, nickel, iron, etc. Resistancebodies may be formed by incorporating conductive filler material, forexample, a bite. 'ron 30 with great accuracy. As the temperature glinfietc, in the cement. Sued a reslsfance required for setting is relativelylow, metal inserts may be molded in the plastic without danger ofloosening during setting and consequently are very firmly held. Moldedarticle's prepared from the cement may be given an impervious surfacefinish by impregnation with parafiine wax, carnauba wax, asphaltic andbituminous material, fats, and the like. This may suitably be 40eifected by immersing the articles in the nielgd wax. By impregnation ofthe molde art1c e with hard waxes of the character of rna b wa theirelasticity and resiliency may fie increased. Where highly elas- 45 ticor resilient molded articles are desired, a suitable filler shouldlikewise be selected; for example, crushed glass.

In connection with the molding of commercial articles I have found itadvanta- 50 geous to admix a small proportion, say M; to

3% of light Hmm'gam- 3gil for example kerosene. wlti e emen ne r cen iasbeen found to be a satlsfactory proportion. The presence of this smallproportion of lubricant oil appears to have the effect of retardingsetltling when admixed Wit-l; tge setting iqui prior to com o t earticle in molding. When the article is comressed, the lubricant oilappears to be 69 orced out, lubricating the surfaces of the die andpreventing sticking thereto. The set of the molded article appears to bein no way affected.

For special uses in which the cement is to be molded or shaped in ahighly plastic conmay be foimth terminals partially embedded in the massand may be provided with insulation formed of the cement, the wholebeing set simultaneously.

The ter nfisinlarinallas used herein designates a superficial fusion ofthe particles of the material and may or may not be accompanied byagglomeration. The term alkali forming metals, as used herein,designates the metals of the group including the alkali and alkalineearth metals.

claim:

1. A cement capable of setting with a solution of phosphoric acid andadapted for press molding. said cement comprising a filler and from 2 to10% of calcium alumina e as its effective bonding constituent.

2. A cement capable of setting with a solution of phosphoric acid andcomprising a filler includ'nv ilica and from 2 to 10% of an aluminate ofan alkalj forming metal as its e co We on mg constituen 3. A cementcapable of setting with a solution of phosphoric acid and comprising afiller including silica and from 2 to 106% of calcium aluminate as itseffective bonding agent.

4. A cement capable of setting with a solution of phosphoric acid andcomprising a filler including silica, an inert material capable ofcombining with water and an aluminate of an alkali forming metal.

5. A cement capable of setting with a solution of phosphoric acid andcomprising a filler including silica, a dehydrating filler and from 2 to10% of an aluminate of an alkali forming metal as its effective bondingconstituent.

6. A cement capable of setting with a solution of phosphoric acid andcomprising a filler including silica, a dehydrating inert material andfrom 2 to 10% of calcium aluminate as its effective bonding constituent.

7. A cement capable of setting with a solution of phosphoric acid andcomprising a filler including silica, alumina and an aluminate of analkali forming metal.

8. A cement capable of setting with a solution of phosphoric acid andcomprisin a filler containing one part of alumina an two parts ofcrushed quartz and from 2 to 10% of an aluminate of an alkali formingmetal.

9. A cement capable of setting with a solution of phosphoric acid andcomprising a filler containing one part of alumina and two parts ofcrushed quartz, and 3 to 4% calcium aluminate.

10. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing as a primarybinding constituent an aluminate of an alkali forming metal, a settingliquid comprising phosphoric acid, the proportion of the latter being atleast sufficient to wet the cement.

11. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing calciumaluminate as a primary binding constituent, a setting liquid comprisingphosphoric acid, the proportion of the latter being at least sufiicientto wet the cement.

12. The method of preparing a plastic mas capable of being molded underpressure which comprises admixing with a cement containing from 2 to 10%of calcium aluminate as a primary binding constituent a setting liquidcomprising phosphoric aci and phosphates, the proportion of the liquidbeing at least sufiicient to wet the cement.

13. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing an aluminateof an alkali forming metal as a primary binding constituent and an inertfiller compound capable of combining with water, a setting liquidcomprising phosphoric acid, the proportion of the latter being at leastsufficient to wet the cement.

14. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing an aluminateof an alkali forming metal as a primary bindin constituent and an inertfiller capable 0 combining with phosphoric acid, a setting liquidcomprising phosphoric acid, the proportion of the latter being from 2 to10%.

15. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing from 2 to 10%of an aluminate of an alkali forming metal and an inert filler includingalumina, a setting liquid comprising phosphoric acid, the proportion ofthe latter being at least sufiicient to wet the cement.

16. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing from 2 to 10%of an aluminate of an alkali forming metal as a primary bindingconstituent and an inert filler including asbestos, a setting liquidcomprising phosphoric acid, the proportion of the latter being at leastsufiicient to wet the cement.

17. The method of preparing a plastic mass capable of being molded underpressure whlch comprises admixing with a cement containing an aluminateof an alkali forming metal as a primary binding constituent and an inertfiller including a material capable of combining with water, a settingliquid comprising phosphoric acid, the proportion of the latter being atleast suflicient to wet the cement, the proportion of the fillermaterial capable of combining with water being selected to control therate of set by varying the concentration of the setting liquid.

18. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing an aluminateof an alkali forming metal as a primary binding constituent and an inertfiller including a material capable of combining with ph m7 horic timecomprising phosphoric acid, the proportion of the latter being at leastsuflicient to wet the cement and the proportion of the filler materialcapable of combining with phosphoric acid being selected to control therate of set by varying the concentration of the setting liquid.

19. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing from 2 to 10%of an aluminate of an alkali forming metal as a primary bindingconstituent and an inert filler containing 20 to 331% of alumina. asetting liquid comprising phosphoric acid, the proportion of the latterbeing at least sufiicient to wet the cement.

20. The method of preparing a plastic mass capable of being molded underpressure whlch comprises admixing with a cement containing 2 to 10% ofan aluminate of an alkali forming metal as a primary 6. COMPOSITIONS,

COATING R PLASTIC.

binding constituent and an inert filler containing 335% of alumina, asetting liquid comprlsing phosphoric acid, the proportion of the latterbeing at least sufiicient to wet the cement.

21. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing with a cement containing an aluminateof an alkali forming metal as a primary binding constituent, a settingliquid comprising ph0sphoric acid and zinc phosphate in proportion atleast sufiicient to wet the cement.

22. The method of pre aring a plastic mass capable of being mo ded underpressure which comprises admixing 100 parts of a cement containing about3% of calcium aluminate and an inert filler containing one part ofalumina to two parts of silica with parts of a setting 1i u1d containingphosphoric acid and zinc p osphate.

23. The method of preparing a plastic mass capable of being molded underpressure which comprises admixing a cement containing from 2 to 10% ofan aluminate of an alkali forming metal as a primary bindingconstituent, a setting liquid comprising phosphoric acid in proportionat least sufficient to wet the cement and a small proportion of a lightlubricating oil.

24. The met od of preparing a plastic mass capable of being molded underpressure which comprises admixing a cement containing from 2 to 10% ofan aluminate of an alkali forming metal, a setting liquid comprisingphosphoric acid in proportion at least suflicient to wet the cement andabout 1% of kerosene.

25. A moldable, setting plastic mass comprising a filler, an aluminateof an alkali formingmetal, plfis'ph dric acid and water.

26. A moldable, setting plastlc mass comprising a filler, at least 2% ofcalcium aluminate, phosphoric acid and wa er. 27. A moldable, settingplastic mass comprising a filler including a substance capable ofcombining with water, at least 2% of an aluminate of an alkali formingmetal, ph0sphoric acid and water.

28. A moldable, setting plastic mass comprising a. filler including asubstance capable of combining with water, about 3% of calciumaluminate, phosphoric acid and water.

29. A moldable, setting plastic mass comprising a filler includingalumina, at least 2% of an aluminate of an alkali forming metal,phosphoric acid and water.

30. A moldable, setting plastic mass comprising a filler includingsilica and alumina, at least 2% of an aluminate of an alkali formingmetal,'phosphoric acid and water.

31. A moldable, setting plastic mass comprising a filler includingsilica and alumina, from 2 to 10% of calcium aluminate, phosphoric acidand water.

32. A moldable plastic mass including a filler, at least 2% of analuminate of an alkali forming metal, a small proportion of a lightlubricating oil, phosphoric acid and water.

WILLIAM HOSKINS.

